Getting over charged by T-Mobile... and not getting any help!

I've been dealing with a billing issue for over 6 months now and nobody at tmobile and I mean NOBODY at tmobile will honor the quote I was given at the store or over the phone when I signed up for the 5g Go plus plan, I was originally quoted 217 and change and was verified over the phone so I  know it's recorded and the bill I received was 267, I called in again because nobody from this company can follow through with their customers, after I called back in they put me back on my old magenta plan, before I hung up with the tmobile supervisor I was told I was gonna be paying 187 and change going forward, I explained to her that I got new phones with the 5g go plus plan and I didn't want any surprises on my bill, she told me that it would only be 187$ going forward, my next bill was well over 300$ because I have the new phones and now I have to pay full price for them. I called back in and talked to another supervisor that told me that they can pit me back and the 5g go plus plan and going forward I would be paying 233.03, my bill after I was quoted 233.03 was actually 267 and change, nobody at this company gives a about honoring  the original price I was misquoted 2 times, now my bill is over 300 because I added Netflix premium and upgraded another phone on my account, it's been nothing but headaches dealing with these tmobile representatives/supervisors that can't do anything but give me different stories and excuses every month I call in because AGAIN Tmobile customer service is CRAP, they don't care that THEY messed up and I now have to to pay more than 30/month than what I was quoted. IT'S A SHAME HOW THEY TREAT CUSTOMERS